JS的ES7支持

1.指数运算符(幂): **

2.Array.prototype.includes(value) : 判断数组中是否包含指定value

1 console.log(2**4); //16
2 
3 let arr = [2,3,4,5,7,8];
4 console.log(arr.includes(1)); //false
5 console.log(arr.includes(3)); //true